As a wide-angle image pickup unit, which can take an image at a wide field angle, a wide-angle camera is known, which uses a wide-angle lens. Also, a total circumferential camera or the like are known, in which a plurality of cameras are disposed in a circumferential direction and images in the total circumferential direction can be taken.
In recent years, there has been a tendency that image data associated with positional data have been increasingly used as map data, and a wide-angle image pickup unit is used to acquire such image data. The wide-angle image pickup unit is installed on a mobile object such as an automobile, and takes images of sceneries around a road at a predetermined interval according to the automobile running.
To use the images thus taken as image data for the preparation of map, it is necessary to identify a position where the object to be measured has been taken or a position of the object to be measured in order to associate the images with the map data. It has been practiced in the past to install a position measuring unit separately on the mobile object, to measure a building with special features or a telephone pole or the like by this position measuring unit, and to associate the image data with the map data.
As described above, the image data and the positional data have been acquired separately in the past. Further, a construction feature of the measuring system was complicated. Troublesome procedures and much time have been needed for associating the image data with the positional data, and these have been placing much burden on an operator.
To solve the problems as described above, the present invention provides a wide-angle image pickup unit and a measuring system, by which it is possible to take an image at wide field angle and to measure a distance to the object to be measured at the same time.